The invention relates to diffuse reflectors, particularly for use as back reflectors.
U.S. Pat. Nos. 5,543,958, 5,663,816, 5,745,203, 5,812,229, 5,594,560, WO 95/12826 describe liquid crystal display devices incorporating a holographic reflector as only one element. The holographic reflectors they specifically refer to are volume holograms. The diffractive principles by which they are operate (multiple Bragg reflections) are fundamentally different from a surface relief structure and the concept of blazing is irrelevant.
U.S. Pat. Nos. 5,936,751, 5,926,293 and 6,014,202 describe complete liquid crystal display devices of which the holographic reflector is a component. U.S. Pat. No. 5,936,751 briefly describes how the off-axis H1 to H2 process can be used to create a holographic surface relief diffuser.
There also exists an article by Kaiser Optical Systems entitled “Holographic Diffusers for LCD backlights and Projection screens” J. M. Tedesco et al, Kaiser Optical Systems, Inc., Ann Arbor, M, “SID 93 digest” which describes control of the direction of diffusion and the cone-angle of diffusion to meet application requirements. Specifically in WO-A-9503935, a transmissive diffusing device which both homogenizes and imparts predetermined directionality to an incident light beam through the application of a microsculpted surface is disclosed.